Chemotherapeutic treatment of leprosy and Pneumocystis carinii infections is performed by the administration of pills of N,N′-diamino-diphenyl sulfone. The pharmaceutical formulation of the sulfone in solution for use as a drug poses technical problems due to the low solubility of N,N′-diamino-diphenyl sulfone in an aqueous medium, therefore, in the present invention, new formulations are presented that allow solubilization of up to 200 mg of sulfone/3 mL, using co-solvents that are compatible with pharmaceutical safe use in humans.
N,N′-diamino-diphenyl sulfone solutions have been reported using the surfactant compound Tween-80, in a ratio of 90% [Helton D R, Osborne D W, Pierson S K, Buonarati M H, Bethem R A., Pharmacokinetic profiles in rats after intravenous, oral, or dermal administration of dapsone, Drug Metabolism and Disposition 28: 925-929 (2000)], Drug Metabolism and Disposition 28: 925-929 (2000)], with the serious disadvantage that Tween-80 is a toxic compound at the necessary concentrations to dissolve sulfone, which precludes its use in humans.
The present invention has the purpose of achieving water-soluble mixtures of N,N′-diamino-diphenyl sulfone for faster absorption of the active molecule with the possibility of applying it in unconscious people and that allows its safe use in human beings as a medication for therapeutic administration in the form of solutions by any systemic route, including all enteral and parenteral routes.
N,N′-diamino-diphenyl sulfone is a drug currently used in the chemotherapy of leprosy and in the prophylaxis against Pneumocystis carinii pneumonia. Recently, N,N′-diamino-diphenyl sulfone (dapsone) has shown other uses as a neuro-protective and anti-epileptic, which frequently require administration to unconscious patients, making it impossible for the administration of solid pharmaceutical formulations. These new applications for dapsone have been patented (patent No. MX 246.892, patent No. MX 264.912) and the soluble forms are more suitable for such applications, because faster drug absorption is required in treatments, compared with the speed of solid formulations.